Panelo said documents showed former President Benigno Aquino III had authorized then Defense Secretary Voltaire Gazmin to sign the agreement on behalf of the Philippines.

Panelo said the Instrument of Ratification, a document deposited with the United Nations, contained the signature of Aquino as proof that the former leader had ratified the articles and clauses of EDCA.

“It is a valid agreement but what we are saying is that it is subject to review and evaluation,” Panelo said, adding that he had already informed President Rodrigo Duterte about the EDCA validity immediately after finding out that EDCA, which the Supreme Court declared constitutional, had Aquino’s signature.

Earlier, Duterte had called for a review of the defense deal, saying it does not bear the signature of a Philippine president.

Under the agreement, the US will be allowed to build structures; store as well as pre-position weapons, defense supplies and materiel; and station troops, civilian personnel and defense contractors, transit and station vehicles, vessels, and aircraft for a period of 10 years.

Last January, the Philippines offered eight bases where the US can build facilities to store equipment and supplies.